Apuanite

General Information:
 Chemical Formula:
Fe++Fe+++4Sb+++4O12S
 Composition:
(Molecular Weight = 990.29 gm)
Iron 28.20 % Fe
Antimony 49.18 % Sb
Sulfur 3.24 % S 
Oxygen 19.39 % O 
 Empirical Formula:
Fe2+Fe3+4Sb4O12S
 IMA Status:
Approved IMA 1978
Physical Properties:
 Cleavage:
[???] Perfect
 Color:
black.
 Density:
5.33
 Diaphaniety:
Opaque
 Hardness:
4-5 - Fluorite-Apatite
 Luster:
Metallic
 Streak:
black
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